3 tablespoons extra virgin olive oil, plus extra to serve
juice of 1/2 lemon
50 g (2 oz) rocket leaves
salt and pepper
Parmesan cheese shavings, to serve
Wrap the tuna tightly in clingfilm and place in a freezer for 20 minutes and then, using a sharp knife, slice into very thin strips.
Meanwhile, cook the pasta in a large saucepan of salted boiling water according to the pack instructions until al dente. Drain the pasta and return to the pan, then toss through the tuna with 1 tablespoon olive oil and lemon juice.
Toss together the rocket and remaining lemon juice and 1 tablespoon oil in a bowl and season.
Spoon the pasta into serving bowls, arrange the rocket salad on top and grind over plenty of black pepper. Serve scattered with the Parmesan shavings and drizzled with the remaining olive oil.